Some methods in GraphicsContextGL and WebGL2RenderingContext exist only for the non-ANGLE code path. Since WebGL 2.0 is infeasible to implement without ANGLE, and has already been disabled for the non-ANGLE code path (!USE(ANGLE)), these methods and overrides should be removed.
As one example, WebGLRenderingContextBase::validateIndexArrayConservative should be removed from the non-ANGLE code path, and the override removed from WebGL2RenderingContext.
<rdar://problem/66399743>
After more thought, fixing up the remaining WebGL 2.0 conformance issues is higher priority than this cleanup. Downgrading to P3 and unassigning myself for the moment.